package cuppics;

import org.junit.Test;

public class Prj16 {

	/**
	 * 2^15 = 32768 and the sum of its digits is 3 + 2 + 7 + 6 + 8 = 26.
	 * 
	 * What is the sum of the digits of the number 2^1000?
	 */
	@Test
	public void test() {
		System.out.println(getSum(1000));
	}

	public int getSum(int bit) {

		int[] buf = new int[bit];
		buf[bit - 1] = 2;
		// 1000 - 1;
		for (int i = 0; i < bit - 1; i++) {

			for (int iter = 0; iter < bit; iter++) {
				buf[iter] *= 2;
			}
			for( int j = bit - 1; j > 0 ; j --){
				int remain = buf[j] % 10;
				buf[j - 1] += buf[j] / 10;
				buf[j] = remain;
			}
		}

		int sum = 0;
		for (int i = 0; i < bit; i++) {
			sum += buf[i];
		}
		return sum;
	}
	
	
	static void print_Arr( int [] arr){
		for( int  i = 0 ; i < arr.length; i ++){
			System.out.println("[" + i + "]=" + arr[i]);
		}
	}
}
